Improved apparatus for leaching tan-bark and obtaining extracts



'vided with my invention.

UNITED STATES PATENT OFFICE.

' WILLIAM II. ALLEN, OF FRYEBURG, MAINE, ASSIGNOR TO I-IIMSELF AND OTISIVARREN, OF SAME PLACE.

Specification forming part of Letters Patent No. 36,048, dated July 29,1862.

` To @ZZ whom it may concern:

specication and represented in the accompanying drawings, of which-`Figure lis a top view, and Fig. 2 a vertical and transverse section, ofa leaching-vat pro- Fig. 3 is a horizontal and longitudinal section ofthe perforated distributing arm or tube, to be hereinafter described.

The purpose of my invention is to distribute water or any otherleaching-liquid in line streams and evenly on the upper surface of amass of bark or other material to be leached.

My invention is specially adapted for extracting tannin from bark, butis equally applicable to leaching wood-ashes for the purpose ofobtaining an alkaline lye therefrom.

. In carrying out my invention I employ a tub or vat, A, furnished witha perforated false bottom or strainer, B, which in the drawings isexhibited as elevated somewhat above the real bottom a, in order thatthere may be a liquor-receiving space, b, between the two.

From the central part of the bottom a a post, c, rises vertically andreceives on its top and gives support to the closed lower end of arotary tubular shaft, O, whoseupper end is open and extends into astuffing-box, d, xed on the lower end of a chambered conduit-elbow, D.The said elbow is fastened tothe side of a crossbar, E, which issupported by two standards, F F, and is extended over the vat, as shownin the drawings.

A horizontal shaft, G, is sustained by a box, g, and a hanger, h,arranged with respect to the tub or vat, as shown in Figs. l and 2. Adriving-pulley, i, is fixed on the outer end of the shaft, while abeveled pinion or gear, 7c, is attached to the inner end of such shaftand engages with another beveled gear, Z, fixed on vthe tubular shaft C.

A hollow or chambered arm, G', extends horizontally from the shaft O,opens into it, is closed at its outer end, and along one side isprovided with a series of openings, m m m m, etc. These openings arearranged at equal distances apart, and as they vary in their distancesfrom the center of the shaft C are increased in size,their areas beingto one another in the proportions of the circumferences of their circlesof revolution, or thereabout, in order that each hole, while the machinemay bein action, may discharge a like amount of liquid on a like extentof surface traversed by it-that is to say, if we suppose the first holeof the series to be situated at any given distance from the axis of thevertical shaft C, and the third hole to be twice that distance from suchaxis, it will be evident that during each entire revolution of the shaftC tho said third hole will pass over twice the surface that the firsthole does, 'and consequently should discharge twice the amount ot'liquidthat may be thrown out of the y iirst,it being supposed that thepressure within the shaft Gis constant, and also that the delivery tothe two holes is not materially impeded by friction. rlhe ratio ofthesizes, therefore, of the several holes will be very nearly that of thecircumferences of circles in which they travel, due allowance being madefor friction.

In the process of leaching bark it has been customary to pour the waterindiscriminately over the surface of the mass, or allow it to stand in alarge quantity on the same. Under these circumstances so rapid apercolation or infiltration of the liquid takes place as to produce avery imperfect extraction of the tannin. The purpose of my invention is-to induce a slow and even percolation of the fluid through the mass ofthe bark, and I accomplish this by suffering hot water to run into theshaft C and from thence into the arm G and out of its perforations whilethe said arm and shaft are in revolution together, so as to cause thearm to pass over the upper surface of a mass of ground bark should benumerous and as near as possible at I claim y equal distances apart, inorder that the dis- My improved leaching apparatus, concharge of theliquid from the lower surface of structed in manner and so to operate,substam the mass of bark upheld by the strainer may tially asrepresented and described.

be uniform. Y The even infiltration of the liquid into and WM' H' ALLENits even discharge from, the muss of berk is Witnesses: e matter ofnecessity in order to obtain the IsAIM-r WARREN, best or most thoroughextraction of the tannin. ASA CHARLES.

